Spontaneous human combustion (SHC) is the alleged process of a human body
catching fire as a result of heat generated by internal chemical action. While no one has
ever witnessed SHC, several deaths involving fire have been attributed to SHC by
investigators and storytellers.

In the literature, spontaneous human combustion is almost exclusively
reserved for corpses. One 17th century tale, however, claims that a German man
self-ignited due to his having drunk an excessive amount of brandy. If drinking a great
quantity of brandy caused self-combustion, there should be many more cases to study than
this isolated report from Germany.

Many of the SHC stories have originated with police investigators who have
been perplexed by partially ignited corpses near unburnt rugs or furniture. "What
else could it be?" they ask. Many of the allegedly spontaneously combusted corpses
are of elderly people who may have been murdered or who may ignited themselves
accidentally. Yet, self-ignition due to dropping a lit cigarette, or ignition due to
another person are ruled out by the investigators as unlikely. Instead, they favor an
explanation which requires belief in an event which has never been witnessed in all of
human history--unverifiable or reliable testimonies to the contrary.

Physical Possibility of SHC

The physical possibilities of spontaneous human combustion are remote. Not
only is the body mostly water, but aside from fat tissue and methane gas, there isn't much
that burns readily in a human body. To cremate a human body requires enormous amounts of
heat over a long period of time. To get a chemical reaction in a human body which would
lead to ignition would require some doing. If the deceased had recently eaten an enormous
amount of hay that was infested with bacteria, enough heat might be generated to ignite
the hay, but not much besides the gut and intestines would probably burn. Or, if the
deceased had been eating the newspaper and drunk some oil, and was left to rot for a
couple of weeks in a well-heated room, his gut might ignite.

It is true that the ignition point of human fat is low, but to get the
fire going would probably require an external source. Once ignited, however, some
researchers think that a "wick
effect" from the body's fat would burn hot enough in certain places to destroy
even bones. To prove that a human being might burn like a candle, Dr. John de Haan of the
California Criminalistic Institute wrapped a dead pig in a blanket, poured a small amount
of gasoline on the blanket, and ignited it. Even the bones were destroyed after five hours
of continuous burning. The fat content of a pig is very similar to the fat content of a
human being. The damage to the pig, according to Dr. De Haan "is exactly the same as
that from supposed spontaneous human combustion."

In their investigation of a number of SHC cases, Dr. Joe Nickell and Dr. John Fisher
found that when the destruction of the body was minimal, the only significant fuel source
was the individual's clothes, but where the destruction was considerable, additional fuel
sources increased the combustion. Materials under the body help retain melted fat that
flows from the body and serves to keep it burning.*

They also found that plausible external sources of ignition, such as candles, lamps,
cigarettes, fireplaces, etc., were rejected by investigators in favor of the implausible
internal spontaneous combustion.

Fact

Scientists believe they have found the secret behind stories of people suddenly bursting into flames.
BBC 1's QED - which brought together the world's top fire experts - looked at cases of spontaneous human combustion from around the world.
And the programme discovered that the so-called wick-effect, in which a body is devoured by flames from its own body fat, is behind the mystery.
Using a dead pig wrapped in cloth, they simulated a human body being burned over a long period and the charred effect was the same as in so-called spontaneous human combustion.
The QED team spoke to Paul Haggarty who as a young fire officer was called to investigate a fatal fire in Pennsylvania. The victim was an elderly widow and what he saw still haunts him.
The victim was consumed by fire except for the legs. Even a wooden table nearby was untouched.

Mr Haggarty said: "There is no way you could explain it. None of the firemen had seen anything like it."
The most recent recorded case in the UK happened in 1992 in northern England.
Again, the woman's legs were left untouched, while the rest of her body was burned to a cinder.
Home Office pathologist Mike Green, who examined the body, does not believe in spontaneous human combustion.

But he said: "The first time you see it you rock back on your heels and your ask yourself 'How is it that the body has been totally consumed and nothing else has been damaged?'
"It beggars belief".
Explanations include balls of lightning or a build up of methane inside the gut.
But forensic scientists are now convinced that the cause of such incidents is the so-called wick effect, started by a source as simple as a cigarette.

This means that in certain rare circumstances a human being can burn like a candle.
But the fact that human bones were completely destroyed remained a mystery, until now.
Even in human crematoria where temperatures are 700-1000 centigrade, the bones are not destroyed.
A pig was used because it closely resembles a human's fat content.
The pig was wrapped in a blanket and a small amount of petrol was poured on it.

After five hours of continuous burning the bones were being destroyed.
Dr De Haan said: "The sort of damage here is exactly the same as that from supposed spontaneous human combustion."
The scientists believe they demonstrated how a case of spontaneous human combustion can occur through normal processes on a person who has been knocked unconscious.
The wick effect means that a person could burn slowly without attracting attention from passers-by.
It also explains why only part of the body, the part which is rich in fat, burns while the rest stays intact.